Russia's Gazprom said Ukraine had failed to pay at least part of its gas debts by a 06:00 GMT deadline and would now have to pay up front for deliveries.
“This decision was taken due to systematic failure of Naftogaz Ukraine to pay. The debt of the company for Russian gas stands at $4.458 billion”- Gazprom said in a statement posted on its website.
Gazprom also announced that it is filing a lawsuit against Naftogaz with the Stockholm Chamber of Commerce Arbitration to seek payment for the $4.5 billion debt.
It should be noted, such a stoppage could also disrupt the gas flow to European countries.